There are many imaging applications in which spatial restraints critically restrict the design of an image acquisition system (e.g., cameras and the lens systems therein). For example, in order for smart/cellular phones to be competitive on the marketplace, these devices must remain small enough to avoid inconveniencing users while being carried (e.g., in a user's pocket) at virtually all times. Similarly, hidden surveillance cameras must be small in order to remain discreet. Many other imaging applications exist in which design space is limited or very restricted for optical and mechanical components.
Although optical zooming in such imaging applications is highly desirable, optical zooming has not been implemented in such imaging applications due to the limited design space available. Moreover, smart/cellular phone cameras have trended towards being thinner and smaller in size. Since many smart/cellular phone cameras have optical axes that lie perpendicular to the thin dimension of device, and conventional optical zooming apparatus rely on movement of opto-mechanical components along the optical axis, such devices are ill-equipped for optical zooming by conventional optical zooming apparatus. Thus, such devices are frequently designed with a single lens or lens unit having a fixed focal length, thereby forgoing optical zooming capability.
Therefore, there is a need for a compact optical zooming apparatus that overcomes restricted spatial requirements.